Re: Data: How Much

Originally Posted by Pauls72

The Panasonic 34230 sensor in the ASI1600 and QHY163 does not support hardware binning.
All software binning does is add or average the pixels together and lower the resolution and shrink the image size.

Hardware binning is pretty much standard on CCD sensors.
It is only the very new, high end CMOS sensors that support hardware binning. The vast majority of CMOS sensors do not support hardware binning.

yes it doesn't do hardware binning !, the camera it'self dose "hardware binning" which is the onboard processor converting it after capture at software level apparently ,which really is software binning ,ahh they make things so confusing

Re: Data: How Much

LOL Henk, a grand per image that's not bad! What are you using for a capture program for the Atik 383L, and in what format are you capturing in.

Stuart, what is the average file size per sub?

The other interesting thing I'm aware of but ignorant about the "How it works" is binning. I have a low end Atik Infinity, I use the Atik capture software (cheating I know) and have seen binning in action, yet don't understand how this adds to the image. It sure speeds light capture in Black and White.

Sorry for the delay, I realize there have been a lot of answers between then and now.
I'm going to be vague and perhaps annoying here and answer the "What is the average file size per sub" and answer, "Who cares?" Or to be less obnoxious, "It depends".
I write "who cares" because hard drive space is dirt cheap now and you can get an 8 tb external hard drive for $150--less if you shop. That's a LOT of imaging data unless you are doing a ton of video.

The less obnoxious answer of "It depends" means that it depends on your camera and binning. A 12 or 14 bit camera will have smaller files than a 16 bit camera, and binning decreases the file size because you have fewer pixels. However, it does NOT matter if you're doing a 30 second sub vs. a 30 minute sub if you're using the same camera and binning settings. The file size is the same.

Others have explained what binning is. I'll just add that I never bin. It makes no sense for my system to bin.

Re: Data: How Much

Originally Posted by yobbo89

My nikon d60 is 10.2 mega pixels and an image is 11.8mb ,my sony a7 is 24mega pixels and an image is 23.4mb, it works out about close to 1mb per megapixel so there must be some correspondence to pixel amount assigned to file size

Hi,

All you've established here is that a larger sensor will have a larger file size. Just because the larger sensor has more pixels gives you no indication of the quality of data contained in those pixels. Did that greater number of pixels capture nothing, background light pollution, bad seeing, guiding errors, satellite tracks, an out of focus condition, or any other abnormalities that constantly plague our images. A 10 megapixel sensor producing great images outperforms a 24 megapixel sensor producing crappy images.

This is now going to get deep. If we compare a perfect image from a 10 megapixel sensor and a perfect image from a 24 megapixel sensor will the larger file be better than the smaller file. It depends. What is the Imaging scale? If my Imaging scale is less than 1 pixel per arcsecond and my current seeing condition is 3 pixels per arcsecond the larger sensor is restricted to what the seeing allows. Once again the file size is not an accurate representation of the quality of the data that is in that file.

Now, let's take this where you want it to go. Let's set up a situation where both our sensors are in outer space. There's nothing in the way, there's no seeing issues, there's no satellite issues, no light pollution issues, and we take images through the same telescope. In this rare and unobtainable case yes the larger file size will have more and better data.

Unfortunately, we have to deal with the hand we are dealt here underneath the atmosphere of our planet. I wish it were that simple to say the larger file will be a better picture. Unfortunately, that's not necessarily so.

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Re: Data: How Much

Just a brief up-date. Have layed my ears back (I've been told many times I reside at the "other" end of the horse) and started to learn how to get plate solving working from within my capture program. As I've gathered here, I need more time on target to capture higher quality data. My thinking is that by plate solving I should be able to get back to the intended victim several nights in a row? (more of a question than statement)

I've had a bit of success, I finally got APT to recognize Stellarium. And I figured out how to get my current target into where I should be able to plate solve. Getting the mount to actually move to where it ought to be will be the next goal. It hasn't been an easy task. I am more of a "visual learner" than a "read it" learner. The videos for what I am attempting to do do have useful information. They also leave a lot out.

I hope I get it all figured out before the flat spot on my forehead (from banging it on the wall) is permanent!

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Re: Data: How Much

I guess there is always the next logical question. How do you know when you've reached the limits of your equipment, environment and your skill?

The image below was captured on three different nights (none of which were great for AP). There was a total of 54 minutes of capture time @ ISO 800 with a Canon 1100D in a 8" SW Quattro. The only thing done to the images was Stacking in DSS with a tweek of the Histogram in DSS.

I should add, I have another nights data I didn't use. The reason I didn't use was there were a lot (probably 80) short (15 Seconds) at ISO 1600. I stacked that bunch separately. To tell the truth all those stacked didn't look as good as a single image @ 150 seconds.

The real sweet spot for my set-up on that target appears to be in the 2 1/2 to 3 minute range. My guiding is working well enough that 10 minute exposures can be done. I did try a couple at ISO 400 for 600 seconds, but wasn't happy with star bloat.

Re: Data: How Much

I went to a talk by Robin Glover 3 days ago in Kettering, United Kingdom. He has produced figures and results to allow for light pollution, sensor quality like thermal noise and read noise to give figures and graphs to show - optimum number of exposures, the duration of each subexposure. Its in the Sharpcap website. I could summarise these when I get the chance to "process" it all out. I am not sure if Sharpcap can operate dSLR but the principles are similar as its a CMOS sensor.